System and Method of Waveform Design for Operation Bandwidth Extension

ABSTRACT

Different numerologies may be used to communicate orthogonal frequency division multiplexing (OFDM)-based signals over different frequency sub-bands of a given carrier. This may allow the OFDM-based signals to efficiently support diverse traffic types. In some embodiments, the numerology of OFDM-based signal depends on a bandwidth of the frequency sub-band over which the OFDM-based signals are transmitted. In some embodiments, the OFDM-based signals are filtered OFDM (f-OFDM) signals, and the pulse shaping digital filter used to generate the f-OFDM signals allows the receiver to mitigate interference between adjacent f-OFDM signals upon reception, thereby allowing f-OFDM signals to be communicated over consecutive carriers without relying on a guard band.

This patent application claims priority to U.S. Provisional ApplicationNo. 62/141,051, filed on Mar. 31, 2015 and entitled “System and Methodof Waveform Design for Operation Bandwidth Extension,” which is herebyincorporated by reference herein as if reproduced in its entirety.

TECHNICAL FIELD

The present invention relates to a system and method for wirelesscommunications, and, in particular embodiments, to a system and methodof waveform design for operation bandwidth extension.

BACKGROUND

In order to provide high throughput rates to individual mobile devicesand further enhance system capacity, next generation wireless networksare likely to use bandwidth allocations that are much broader than the20 megahertz (MHz) carriers used in conventional Long Term Evolution(LTE) networks. In some cases, the bandwidth allocations may exceed 100MHz for carriers having center frequencies below or above 6 gigahertz(GHz). Techniques for supporting such large bandwidth allocations areneeded.

One technique for increasing throughput is carrier aggregation, whichuses multiple carriers to communicate data to a single mobile device.However, conventional orthogonal frequency division multiplexed (OFDM)carrier aggregation utilizes scalable sampling frequencies and FastFourier Transform (FFT) sizes, meaning that broader bandwidthallocations utilize higher sampling frequencies and larger FFT sizes,which increase computational complexity. Additionally, conventional OFDMcarrier aggregation requires that the same sub-carrier spacings are usedfor each of the aggregated carriers. As a result, conventional OFDMcarrier aggregation may be ill-suited for bandwidth allocations inexcess of 20 MHz.

SUMMARY OF THE INVENTION

Technical advantages are generally achieved, by embodiments of thisdisclosure which describe system and method of waveform design foroperation bandwidth extension.

In accordance with an embodiment, a method for transmitting signals isprovided. In this example, the method comprises transmitting a firstorthogonal frequency division multiplexing (OFDM)-based signal over afirst frequency sub-band of a carrier and a second OFDM-based signalover a second frequency sub-band of the carrier. The first frequencysub-band has a first bandwidth and a first numerology based on the firstbandwidth. The second frequency sub-band has a second bandwidth and asecond numerology based on the second bandwidth. An apparatus forperforming this method is also provided.

In accordance with another embodiment, a method for receiving signals isprovided. In this example, the method comprises receiving a firstorthogonal frequency division multiplexing (OFDM)-based signal over afirst frequency sub-band of a carrier and a second OFDM-based signalover a second frequency sub-band of the carrier. The first frequencysub-band has a first bandwidth and a first numerology based on the firstbandwidth, the second frequency sub-band has a second bandwidth and asecond numerology based on the second bandwidth. An apparatus forperforming this method is also provided.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and theadvantages thereof, reference is now made to the following descriptiontaken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a diagram of an embodiment wireless network;

FIGS. 2A-2B are diagrams depicting how filtered OFDM (f-OFDM) signalsare generated;

FIGS. 3A-3B are additional diagrams depicting how f-OFDM signals aregenerated;

FIG. 4 is a flowchart of an embodiment method for communicating f-OFDMsignals;

FIG. 5 is a diagram of a conventional OFDM carrier aggregation format;

FIG. 6 is another diagram of a conventional OFDM carrier aggregationformat;

FIG. 7 is a diagram of a conventional OFDM extended carrier format;

FIG. 8 is a diagram of f-OFDM signals transmitted over consecutivefrequency sub-bands;

FIG. 9 is another diagram of f-OFDM signals transmitted over consecutivefrequency sub-bands;

FIG. 10 is a diagram of a set of predefined carriers types for acellular communication system;

FIG. 11 is a diagram of an embodiment f-OFDM carrier aggregation format;

FIG. 12 is a diagram of another embodiment f-OFDM carrier aggregationformat;

FIG. 13 is a diagram of yet another embodiment f-OFDM carrieraggregation format;

FIG. 14 is a diagram of yet another embodiment f-OFDM carrieraggregation format;

FIG. 15 is a diagram of a set of predefined carrier types for amillimeter wave (mmW) communication system;

FIG. 16 is a diagram of a set of predefined sub-band types for a mmWcommunication system;

FIG. 17 is a diagram of yet another embodiment f-OFDM carrieraggregation format;

FIG. 18 is a diagram of yet another embodiment f-OFDM carrieraggregation format;

FIG. 19 is a diagram of an embodiment processing system; and

FIG. 20 is a diagram of an embodiment transceiver.

Corresponding numerals and symbols in the different figures generallyrefer to corresponding parts unless otherwise indicated. The figures aredrawn to clearly illustrate the relevant aspects of the embodiments andare not necessarily drawn to scale.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The structure, manufacture and use of the embodiments are discussed indetail below. It should be appreciated, however, that the presentinvention provides many applicable inventive concepts that can beembodied in a wide variety of specific contexts. The specificembodiments discussed are merely illustrative of specific ways to makeand use the invention, and do not limit the scope of the invention. Asreferred to herein, a frequency sub-band may include an entire carrier,or a portion of a carrier. Hence, different frequency sub-bands may bedifferent carriers, or portions of the same carrier.

As mentioned above, conventional OFDM carrier aggregation utilizesscalable sampling frequencies and FFT sizes. As a result, conventionalOFDM carrier aggregation may be ill-suited for bandwidth allocations inexcess of 20 MHz, as the high sampling frequencies and large FFT sizesrequired to support such large bandwidth allocations may significantlyincrease the implementation complexity of conventional OFDM carrieraggregation. Also, conventional OFDM carrier aggregation requires thatthe same physical layer parameters are used to communicate OFDM signalsover a given carrier. The set of physical layer parameters used tocommunicate a signal are collectively referred to as the “numerology” ofthe signal, and may include a combination, or subset, of a transmissiontime interval (TTI) used to transmit the signal, a symbol duration ofsymbols carried by the signal, a cyclic prefix (CP) length of symbolscarried by the signal, and/or a sub-carrier spacing between sub-carrierfrequencies over which the signal is transmitted. Different physicallayer parameters may be better suited for communicating differenttraffic types. For example, a short TTI may reduce latency and thereforebe better suited for delay-sensitive traffic. A longer TTI may reducescheduling signaling overhead and therefore be better suited for delaytolerant traffic. Because conventional OFDM carrier aggregation uses thesame numerology for all signals communicated over a given carrier, anetwork and/or user may experience a reduction in bandwidth utilizationefficiency and/or performance when conventional OFDM carrier aggregationis used to transport different traffic types over the same carrier.Moreover, conventional OFDM carrier aggregation relies on a guard bandthat is at least fifty multiples of the sub-carrier spacing to mitigateinter-carrier interference, which adds significant overhead to thesignals. Accordingly, an efficient alternative to conventional OFDMcarrier aggregation is desired.

Embodiments of this disclosure use different numerologies to communicatef-OFDM signals or single carrier frequency division multiple access(SC-FDMA) signals over different frequency sub-bands of a given carrier,which allows the f-OFDM or SC-FDMA signals to efficiently supportdiverse traffic. For example, delay sensitive traffic (e.g., voice,mobile gaming) may be communicated over an f-OFDM signal with arelatively short TTI to reduce latency, and delay tolerant traffic(e.g., email, text messages) may be communicated over an f-OFDM signalwith a relatively long TTI to improve bandwidth utilization efficiency.Additionally, the pulse shaping digital filter used to generate f-OFDMsignals may allow the receiver to mitigate interference between adjacentf-OFDM signals upon reception, thereby allowing f-OFDM signals to becommunicated over consecutive carriers without relying on a guard band.In some embodiments, the numerology of an f-OFDM or SC-FDMA signaldepends on a bandwidth of the frequency sub-band over which the f-OFDMor SC-FDMA signal is transmitted. For example, f-OFDM/SC-FDMA signalscommunicated over wider frequency sub-bands may typically have widersubcarrier spacings, shorter symbol durations, shorter TTI lengths andshorter cyclic prefixes than f-OFDM/SC-FDMA signals communicated overnarrower frequency sub-bands. For example, f-OFDM/SC-FDMA signalscommunicated over different 20 megahertz (MHz) sub-bands may havedifferent numerologies. These and other aspects are explained in greaterdetail below. While much of this disclosure describes embodiments forcommunicating f-OFDM signals, it should be appreciated that thoseembodiments can also be applied to communicate any OFDM-based signals,including SC-FDMA signals.

FIG. 1 is a diagram of a wireless network 100 for communicating data.The wireless network 100 includes a base station 110 having a coveragearea 101, a plurality of mobile devices 120, and a backhaul network 130.As shown, the base station 110 establishes uplink (dashed line) and/ordownlink (dotted line) connections with the mobile devices 120, whichserve to carry data from the mobile devices 120 to the base station 110and vice-versa. Data carried over the uplink/downlink connections mayinclude data communicated between the mobile devices 120, as well asdata communicated to/from a remote-end (not shown) by way of thebackhaul network 130. As used herein, the term “base station” refers toany component (or collection of components) configured to providewireless access to a network, such as an evolved NodeB (eNB), amacro-cell, a femtocell, a Wi-Fi access point (AP), or other wirelesslyenabled devices. Base stations may provide wireless access in accordancewith one or more wireless communication protocols, e.g., long termevolution (LTE), LTE advanced (LTE-A), High Speed Packet Access (HSPA),Wi-Fi 802.11a/b/g/n/ac. As used herein, the term “mobile device” refersto any component (or collection of components) capable of establishing awireless connection with a base station. The terms “mobile device,”“user equipment (UE),” and “mobile station (STA)” are usedinterchangeably throughout this disclosure. In some embodiments, thenetwork 100 may comprise various other wireless devices, such as relays,low power nodes, etc.

f-OFDM signals are generated by applying a pulse shaping digital filterto OFDM signals. The pulse shaping digital filters used to generatef-OFDM signals are referred to as f-OFDM filters throughput thisdisclosure. FIG. 2A is a diagram showing how f-OFDM signals aregenerated by applying f-OFDM filters 201, 202 to OFDM signals 210, 220.As shown, the OFDM signal 210 spans an N megahertz (MHz) frequencysub-band, and the OFDM signal 220 spans an M MHz frequency sub-band,where N and M are positive integers, and N is greater than or equal toM. FIG. 2B is a diagram showing the f-OFDM signals 211, 221 that resultfrom applying the f-OFDM filters 201, 202 to the OFDM signals 210, 220.In some embodiments, the f-OFDM filters 201, 202 produce f-OFDM signalshaving different numerologies, in which case the f-OFDM signal 210 andthe f-OFDM signal 220 exhibit different numerologies than one another.The numerologies of the f-OFDM signals 211, 221 may depend on thebandwidth of the N MHz frequency sub-band and the M MHz frequencysub-band, respectively.

In some embodiments, a single f-OFDM filter may be used to generatemultiple f-OFDM signals. FIG. 3A is a diagram showing how f-OFDM signalsare generated by applying f-OFDM filters 301, 302 to OFDM signals 310,320, 330, 340, 350. FIG. 3B is a diagram showing the f-OFDM signals 311,321, 331, 342, 352 that result from applying the f-OFDM filters 301, 302to the OFDM signals 310, 320, 330, 340, 350. Specifically, the f-OFDMsignals 311, 321, 331 are generated by applying the f-OFDM filter 301 tothe OFDM signals 310, 320, 330 (respectively), and the f-OFDM signals342, 352 are generated by applying the f-OFDM filter 302 to the OFDMsignals 340, 350 (respectively). F-OFDM signals generated from the samef-OFDM filter may have the same numerology. Thus, the f-OFDM signals311, 321, 331 have the same numerology as one another, while the f-OFDMsignals 342, 352 have the same numerology as one another. F-OFDM signalsgenerated from different f-OFDM filters may have different numerologies.Thus, the f-OFDM signals 311, 321, 331 may have a different numerologythan the f-OFDM signals 342, 352.

FIG. 4 is a flowchart of an embodiment method 400 for communicatingf-OFDM signals having different numerologies over different frequencysub-bands, as might be performed by a transmit point. The transmit pointmay be any device that transmits wireless signals, includingnetwork-side devices (e.g., base stations) and user-side devices (e.g.,UEs). At step 410, the transmit point generates a first f-OFDM signal byapplying a first f-OFDM filter to a first OFDM signal. At step 420, thetransmit point generates a second f-OFDM signal by applying a secondf-OFDM filter to a second OFDM signal. At step 430, the transmit pointtransmits the first f-OFDM signal over a first frequency sub-band, whiletransmitting the second f-OFDM signal over a second frequency sub-band.The first frequency sub-band has a different bandwidth than the secondfrequency sub-band. In some embodiments, the f-OFDM signals havenumerologies based on the bandwidth of the respective frequencysub-bands over which the f-OFDM signals are transmitted, in which casethe first f-OFDM signal has a different numerology than the secondf-OFDM signal.

Conventional OFDM carrier aggregation communicates data to a single UEover multiple carriers to increase the overall throughput provided tothe UE. Conventional OFDM carrier aggregation may also communicate datato multiple UEs over multiple carriers to enhance system capacity. Asdiscussed above, conventional OFDM carrier aggregation utilizes the samenumerology for signals communicated over each of the carriers, andrequires that consecutive carriers be separated by a guard band that isat least fifty multiples of the corresponding sub-carrier spacing tomitigate interference between the OFDM signals below a threshold. FIG. 5is a diagram of OFDM signals 510, 520 transmitted over consecutive K MHzcarriers (K is an integer) in accordance with a conventional OFDMcarrier aggregation scheme. As shown, the K MHz carriers are consecutivecarriers in the frequency domain, and are separated by a guard band 515.Conventional OFDM carrier aggregation requires that the guard band 515is at least fifty multiples of a subcarrier spacing of the K MHzcarriers. The guard band 515 mitigates interference between the OFDMsignals 510, 520. The relative size of the guard band 515 depends on thebandwidth of the K MHz carriers. For example, 1.25 megahertz (MHz) OFDMcarriers must be separated by a guard band that is fifty-two multiplesof the sub-carrier spacing of the 1.25 MHz carriers, and largerbandwidth OFDM carriers (e.g., 2.5 MHz, 5 MHz, . . . 20 MHz) must beseparated by correspondingly wider guard bands. Conventional OFDMcarrier aggregation also requires that the OFDM signals 510, 520 betransmitted using the same numerologies. Numerologies for OFDM signalscommunicated using conventional OFDM carrier aggregation are listed inTable 1 below:

TABLE 1 Channel Bandwidth (MHz) 1.25 2.5 5 10 15 20 Frame Duration (ms)10 Subframe Duration (ms) 1 Sub-carrier Spacing (kHz) 15 SamplingFrequency (MHz) 1.92 3.84 7.68 15.36 23.04 30.72 FFT Size 128 256 5121024 1536 2048 Occupied Sub-carriers 76 151 301 601 901 1201 (inc. DCsub-carrier) Guard Sub-carriers 52 105 211 423 635 847 Number ofResource Blocks 6 12 25 50 75 100 Occupled Channel 1.140 2.265 4.5159.015 13.515 18.015 Bandwidth (MHz) DL Bandwidth Efficiency 77.1% 90%90% 90% 90% 90% OFDM Symbols/Subframe 7/6 (short/long CP) CP Length(Short CP) (μs) 5.2 (first symbol)/4.69 (six following symbols) CPLength (Long CP) (μs) 16.67

Conventional OFDM carrier aggregation may also communicate data overnon-consecutive carriers. FIG. 6 is a diagram of OFDM signals 610, 620are transmitted over non-consecutive K MHz carriers (K is an integer) inaccordance with a conventional OFDM carrier aggregation scheme. Similarto OFDM signals communicated over consecutive carriers, conventionalOFDM carrier aggregation requires that the OFDM signals 610, 620communicated over non-consecutive carriers use the same numerologies.

One alternative to conventional OFDM carrier aggregation is to transmitan OFDM signal over an extended carrier having a bandwidth that exceeds20 MHz, which is the largest carrier bandwidth available in fourthgeneration Long Term Evolution (LTE) networks. FIG. 7 is a diagram of anOFDM signal 710 transmitted over an L MHz carrier (L is an integerlarger than 20). Although this approach avoids overhead associated withthe guard band utilized in conventional OFDM carrier aggregation,transmitting an OFDM signal over an extended carrier (e.g., greater than20 MHz) also has drawbacks, such as requiring a higher samplingfrequency and larger fast Fourier transform (FFT) size. Additionally, anOFDM signal transmitted over an extended carrier would still utilize asingle numerology for all data carried by the OFDM signal, and wouldtherefore exhibit reduced bandwidth utilization efficiency and/orperformance when carrying different traffic types.

Embodiments of this disclosure communicate f-OFDM signals overconsecutive frequency sub-bands that are separated by a guard band thatis less than twenty multiples of a subcarrier spacing of one of thecarriers. FIG. 8 is a diagram of f-OFDM signals 810, 820 transmittedover consecutive frequency sub-bands that are separated by a guard band815 that is less than twenty multiples of a subcarrier spacing of one ofthe frequency sub-bands. In one embodiment, the guard band 815 is lessthan or equal to ten multiples of the sub-carrier spacing of one of thef-OFDM signals 810, 820. In another embodiment, the guard band 815 isless than or equal to five multiples of the sub-carrier spacing of oneof the f-OFDM signals 810, 820. In yet another embodiment, the guardband 815 is less than or equal to three multiples of the sub-carrierspacing of one of the f-OFDM signals 810, 820. In yet anotherembodiment, the guard band 815 is less than or equal to the sub-carrierspacing of one of the f-OFDM signals 810, 820.

The f-OFDM signals 810, 820 may be transmitted to the same receiver(e.g., the same UE) or to different receivers. The respective frequencysub-bands over which the f-OFDM signals 810, 820 are transmitted mayhave the same subcarrier spacing or different subcarrier spacings. Whenthe respective frequency sub-bands have different subcarrier spacings,the guard band 815 is less than twenty multiples of the wider of the twosubcarrier spacings. In some embodiments, the guard band 815 is alsoless than twenty multiples of the narrower of the two subcarrierspacings. In other embodiments, the guard band 815 is less than thewider of the two subcarrier spacings, but greater than twenty multiplesof the narrower of the two subcarrier spacings.

Embodiments of this disclosure communicate f-OFDM signals overconsecutive frequency sub-bands that are not separated by a guard band.FIG. 9 is a diagram of f-OFDM signals 910, 920 transmitted overconsecutive frequency sub-bands that that are not separated by a guardband. The f-OFDM signals 910, 920 may be transmitted to the samereceiver or to different receivers.

In some embodiments, f-OFDM signals are communicated over aggregatedcarriers. In such embodiments, there may be a predefined set of carrierbandwidths for a wireless network, with each carrier bandwidth havingone or more predefined numerologies. FIG. 10 is a diagram of a set ofpredefined carrier types 1000 for a cellular communication system. Inthis example, the set of predefined carriers types 1000 includes a firstcarrier type (Type-1) with a 2.5 MHz bandwidth, a second carrier type(Type-2) with a 5 MHz bandwidth, a third carrier type (Type-3) with a 10MHz bandwidth, and a fourth carrier type (Type-4) with a 20 MHzbandwidth. Other examples are also possible. Numerologies for the set ofpredefined carrier types 1000 are listed in Table 2.

TABLE 2 SC Spacing (kHz) 7.5 7.5 7.5 7.5 15 30 60 120 Carrier 2.5 5 1015 20 20 20 20 Bandwidth (MHz) Number of 300 600 1200 1800 1200 600 300150 subcarriers FFT Size 512 1024 2048 2048 2048 1024 512 256 Sampling3.84 7.68 15.36 15.36 30.72 30.72 30.72 30.72 Frequency (MHz)

FIGS. 11-14 are diagrams of various f-OFDM carrier aggregation formatsgenerated from the set of predefined carrier bandwidths 1000. FIG. 11 isa diagram of a 100 MHz f-OFDM carrier aggregation format that includesfive 20 MHz carriers that are consecutive in the frequency domain. FIG.12 is a diagram of a 100 MHz f-OFDM carrier aggregation format thatincludes four 20 MHz carriers, one 10 MHz carrier, and two 5 MHzcarriers that are consecutive in the frequency domain. FIG. 13 is adiagram of a 150 MHz f-OFDM carrier aggregation format that includes six20 MHz carriers and three 10 MHz carriers that are consecutive in thefrequency domain. FIG. 14 is a diagram of a 200 MHz f-OFDM carrieraggregation format that includes ten 20 MHz carriers that areconsecutive in the frequency domain. Embodiment f-OFDM carrieraggregation formats may include any combination of predefined carriers.For example, a 50 MHz f-OFDM carrier aggregation format may aggregatetwo 20 MHz bandwidths with a 10 MHz bandwidth. Embodiments may alsocarriers with different bandwidths and/or numerologies, such a 40 MHzcarrier. In some embodiments, f-OFDM carrier aggregation is achieved byaggregating multiple carriers having the same numerology.

FIG. 15 is a diagram of a set of predefined carrier types 1500 for amillimeter wave (mmW) communication system. In this example, the set ofpredefined carrier types 1500 includes a first mmW carrier type (Type-1)with a 1 GHz bandwidth, and a second mmW carrier type (Type-2) with a 2GHz bandwidth. Phase noise may be a factor used to determine thesubcarrier spacing in mmW bands. A subcarrier spacing of between 600 KHzand 10 MHz may be used for mmW bands and/or frequency sub-bands between6 GHz and 100 GHz. In an embodiment, scalable subcarrier spacing isachieved by using a 1.2 MHz subcarrier spacing for frequency sub-bandsbetween 6 GHz and 28 GHz, a 4.8 MHz subcarrier spacing for frequencysub-bands between 28 GHz and 50 GHz, and a 9.6 MHz subcarrier spacingfor frequency sub-bands between 50 GHz and 100 GHz. Other examples arealso possible. Numerologies for the set of predefined carrier types 1500are listed in Table 3.

TABLE 3 Carrier 1 2 1 2 1 2 Bandwidth (GHz) SC Spacing 1.2 1.2 4.8 4.89.6 9.6 (MHz) Number of 750 1500 187.5 375 93.75 187.5 Subcarriers FFTSize 1024 2048 256 512 128 256 Sampling 1228.8 2457.6 1228.8 2457.61228.8 2457.6 frequency (MHz)

In some embodiments, mmW carrier types are fragmented into frequencysub-bands having a smaller bandwidth than the mmW carrier types depictedin FIG. 15. FIG. 16 is a diagram of a set of predefined frequencysub-band types 1600 for a mmW communication system. In this example, theset of predefined frequency sub-band types 1600 includes a first mmWsub-band type (Type-1) with a 200 MHz bandwidth, a second mmW sub-bandtype (Type-2) with a 400 MHz bandwidth, and a third mmW sub-band type(Type-3) with a 800 MHz bandwidth. Numerologies for the set ofpredefined frequency sub-band types 1600 are listed in Table 4.

TABLE 4 Sub-band Bandwidth (MHz) 200 400 400 800 800 SC spacing (MHz)1.2 1.2 4.8 4.8 9.6 Number of subcarriers 150 300 75 150 75 FFT Size 256512 128 256 128 Sampling frequency (MHz) 307.2 614.4 614.4 1228.8 1228.8

It should be appreciated that the numerologies and sub-band bandwidthslisted in Tables 2-4 are provided as examples, and that embodiments ofthis disclosure may use numerologies and/or sub-band bandwidths that arenot explicitly listed in those tables. It should also be appreciatedthat bandwidths can be fragmented into two sub-bands, each of which canapply different numerologies.

FIGS. 17-18 are diagrams of various f-OFDM carrier aggregation formatsgenerated from the set of predefined sub-band types 1600 depicted inFIG. 16. FIG. 17 is a diagram of a 2 GHz f-OFDM sub-band aggregationformat that includes five 400 MHz sub-bands. FIG. 18 is a diagram of a 2GHz f-OFDM sub-band aggregation format that includes four 400 MHzsub-bands and two 200 MHz sub-bands.

In some millimeter wave communication systems, numerologies may be basedon sub-carrier spacing. Numerologies for such an example are listed intable 5.

TABLE 5 SC Spacing (MHz) 1.2 4.8 9.6 Useful Symbol Duration (us) 0.83330.208 0.104 CP length (μs) 0.208 0.052 0.026 Number of Symbols per TTI48 192 384 TTI (μs) 50 50 50 CP overhead 20.00% 20.00% 20.00%

FIG. 19 is a block diagram of an embodiment processing system 1900 forperforming methods described herein, which may be installed in a hostdevice. As shown, the processing system 1900 includes a processor 1904,a memory 1906, and interfaces 1910-1914, which may (or may not) bearranged as shown in FIG. 19. The processor 1904 may be any component orcollection of components adapted to perform computations and/or otherprocessing related tasks, and the memory 1906 may be any component orcollection of components adapted to store programming and/orinstructions for execution by the processor 1904. In an embodiment, thememory 1906 includes a non-transitory computer readable medium. Theinterfaces 1910, 1912, 1914 may be any component or collection ofcomponents that allow the processing system 1900 to communicate withother devices/components and/or a user. For example, one or more of theinterfaces 1910, 1912, 1914 may be adapted to communicate data, control,or management messages from the processor 1904 to applications installedon the host device and/or a remote device. As another example, one ormore of the interfaces 1910, 1912, 1914 may be adapted to allow a useror user device (e.g., personal computer (PC), etc.) tointeract/communicate with the processing system 1900. The processingsystem 1900 may include additional components not depicted in FIG. 19,such as long term storage (e.g., non-volatile memory, etc.).

In some embodiments, the processing system 1900 is included in a networkdevice that is accessing, or part otherwise of, a telecommunicationsnetwork. In one example, the processing system 1900 is in a network-sidedevice in a wireless or wireline telecommunications network, such as abase station, a relay station, a scheduler, a controller, a gateway, arouter, an applications server, or any other device in thetelecommunications network. In other embodiments, the processing system1900 is in a user-side device accessing a wireless or wirelinetelecommunications network, such as a mobile station, a user equipment(UE), a personal computer (PC), a tablet, a wearable communicationsdevice (e.g., a smartwatch, etc.), or any other device adapted to accessa telecommunications network.

In some embodiments, one or more of the interfaces 1910, 1912, 1914connects the processing system 1900 to a transceiver adapted to transmitand receive signaling over the telecommunications network. FIG. 20 is ablock diagram of a transceiver 2000 adapted to transmit and receivesignaling over a telecommunications network. The transceiver 2000 may beinstalled in a host device. As shown, the transceiver 2000 comprises anetwork-side interface 2002, a coupler 2004, a transmitter 2006, areceiver 2008, a signal processor 2010, and a device-side interface2012. The network-side interface 2002 may include any component orcollection of components adapted to transmit or receive signaling over awireless or wireline telecommunications network. The coupler 2004 mayinclude any component or collection of components adapted to facilitatebi-directional communication over the network-side interface 2002. Thetransmitter 2006 may include any component or collection of components(e.g., up-converter, power amplifier, etc.) adapted to convert abaseband signal into a modulated carrier signal suitable fortransmission over the network-side interface 2002. The receiver 2008 mayinclude any component or collection of components (e.g., down-converter,low noise amplifier, etc.) adapted to convert a carrier signal receivedover the network-side interface 2002 into a baseband signal. The signalprocessor 2010 may include any component or collection of componentsadapted to convert a baseband signal into a data signal suitable forcommunication over the device-side interface(s) 2012, or vice-versa. Thedevice-side interface(s) 2012 may include any component or collection ofcomponents adapted to communicate data-signals between the signalprocessor 2010 and components within the host device (e.g., theprocessing system 1900, local area network (LAN) ports, etc.).

The transceiver 2000 may transmit and receive signaling over any type ofcommunications medium. In some embodiments, the transceiver 2000transmits and receives signaling over a wireless medium. For example,the transceiver 2000 may be a wireless transceiver adapted tocommunicate in accordance with a wireless telecommunications protocol,such as a cellular protocol (e.g., long-term evolution (LTE), etc.), awireless local area network (WLAN) protocol (e.g., Wi-Fi, etc.), or anyother type of wireless protocol (e.g., Bluetooth, near fieldcommunication (NFC), etc.). In such embodiments, the network-sideinterface 2002 comprises one or more antenna/radiating elements. Forexample, the network-side interface 2002 may include a single antenna,multiple separate antennas, or a multi-antenna array configured formulti-layer communication, e.g., single input multiple output (SIMO),multiple input single output (MISO), multiple input multiple output(MIMO), etc. In other embodiments, the transceiver 1900 transmits andreceives signaling over a wireline medium, e.g., twisted-pair cable,coaxial cable, optical fiber, etc. Specific processing systems and/ortransceivers may utilize all of the components shown, or only a subsetof the components, and levels of integration may vary from device todevice.

Although this invention has been described with reference toillustrative embodiments, this description is not intended to beconstrued in a limiting sense. Various modifications and combinations ofthe illustrative embodiments, as well as other embodiments of theinvention, will be apparent to persons skilled in the art upon referenceto the description. It is therefore intended that the appended claimsencompass any such modifications or embodiments.

What is claimed is:
 1. A method for transmitting signals, the methodcomprising: transmitting, by a transmit point, a first orthogonalfrequency division multiplexing (OFDM)-based signal over a firstfrequency sub-band of a carrier and a second OFDM-based signal over asecond frequency sub-band of the carrier, the first frequency sub-bandhaving a first bandwidth and a first numerology based on the firstbandwidth, the second frequency sub-band having a second bandwidth and asecond numerology based on the second bandwidth.
 2. The method of claim1, wherein the first numerology is different than the second numerology.3. The method of claim 1, wherein the first OFDM-based signal and thesecond OFDM-base signal are filtered orthogonal frequency divisionmultiplexed (f-OFDM) signals.
 4. The method of claim 3, wherein a firstfilter associated with the first OFDM-based signal contains at least thefirst frequency sub-band, and a second filter associated with the secondOFDM-based signal contains at least the second frequency sub-band. 5.The method of claim 1, wherein the first OFDM-based signal and thesecond OFDM-base signal are single carrier frequency division multipleaccess (SC-FDMA) signals.
 6. The method of claim 1, wherein transmittingthe first OFDM-based signal over the first frequency sub-band of thecarrier and the second OFDM-based signal over the second frequencysub-band of the carrier comprises: transmitting a first OFDM-basedsymbol over the first frequency sub-band of the carrier and a secondOFDM-based symbol over the second frequency sub-band of the carrier, thefirst OFDM-based symbol being communicated during the same time periodas the second OFDM-based symbol.
 7. The method of claim 1, wherein thefirst numerology of the first frequency band is different than thesecond numerology of the second frequency band such that the firstOFDM-based signal is communicated in accordance with at least onedifferent physical layer parameter than the second OFDM-based signal. 8.The method of claim 7, wherein the first OFDM-based signal iscommunicated in accordance with a different transmission time interval(TTI) than the second OFDM-based signal.
 9. The method of claim 7,wherein the first OFDM-based signal carries symbols having a differentsymbol duration than symbols carried by the second OFDM-based signal.10. The method of claim 7, wherein the first OFDM-based signal carriessymbols having a different cyclic prefix (CP) length than symbolscarried by the second OFDM-based signal.
 11. The method of claim 7,wherein the first OFDM-based signal and the second OFDM-based signal arecommunicated over sub-carriers that have a different sub-carrier spacingthan one another.
 12. The method of claim 7, wherein numerologies of thefirst frequency band and the second frequency band are based onbandwidths of the respective frequency bands, the first frequency bandhaving a different bandwidth than the second frequency band.
 13. Themethod of claim 7, wherein the first frequency band and the secondfrequency band have the same bandwidth.
 14. The method of claim 1,wherein the first frequency band and the second frequency band areseparated by a guard band that is less than or equal to twenty multiplesof a sub-carrier spacing of one of the first frequency band and thesecond frequency band.
 15. The method of claim 14, wherein the guardband is less than or equal to ten multiples of the sub-carrier spacingof one of the first frequency band and the second frequency band. 16.The method of claim 14, wherein the guard band is less than or equal tofive multiples of the sub-carrier spacing of one of the first frequencyband and the second frequency band.
 17. The method of claim 14, whereinthe guard band is less than or equal to three multiples of thesub-carrier spacing of one of the first frequency band and the secondfrequency band.
 18. The method of claim 14, wherein the guard band isequal to the sub-carrier spacing of one of the first frequency band andthe second frequency band.
 19. The method of claim 1, wherein the firstfrequency band and the second frequency band are contiguous in thefrequency domain such that the first frequency band and the secondfrequency band are not separated by a guard band.
 20. The method ofclaim 19, wherein the first frequency band and the second frequency bandhave different bandwidths.
 21. The method of claim 1, wherein the methodfurther comprises aggregating the first OFDM-based signal and the secondOFDM-based signal into one signal spanning both the first frequency bandand the second frequency band prior to transmitting the first OFDM-basedsignal and the second OFDM-based signal.
 22. The method of claim 21,wherein a bandwidth of the frequency band is equal to or greater than 40megahertz (MHz).
 23. A transmit point comprising: a processor; and acomputer readable storage medium storing programming for execution bythe processor, the programming including instructions to: transmit afirst orthogonal frequency division multiplexing (OFDM)-based signalover a first frequency sub-band of a carrier and a second OFDM-basedsignal over a second frequency sub-band of the carrier, the firstfrequency sub-band having a first bandwidth and a first numerology basedon the first bandwidth, the second frequency sub-band having a secondbandwidth and a second numerology based on the second bandwidth.
 24. Amethod for receiving signals, the method comprising: receiving, by areceive point, a first orthogonal frequency division multiplexing(OFDM)-based signal over a first frequency sub-band of a carrier and asecond OFDM-based signal over a second frequency sub-band of thecarrier, the first frequency sub-band having a first bandwidth and afirst numerology based on the first bandwidth, the second frequencysub-band having a second bandwidth and a second numerology based on thesecond bandwidth.
 25. The method of claim 24, wherein the firstnumerology is different than the second numerology.
 26. The method ofclaim 24, wherein the first OFDM-based signal and the second OFDM-basesignal are filtered orthogonal frequency division multiplexed (f-OFDM)signals.
 27. The method of claim 26, wherein a first filter associatedwith the first OFDM-based signal contains at least the first frequencysub-band, and a second filter associated with the second OFDM-basedsignal contains at least the second frequency sub-band.
 28. The methodof claim 24, wherein the first OFDM-based signal and the secondOFDM-base signal are single carrier frequency division multiple access(SC-FDMA) signals.
 29. The method of claim 24, wherein receiving thefirst OFDM-based signal over the first frequency sub-band of the carrierand the second OFDM-based signal over the second frequency sub-band ofthe carrier comprises: receiving a first OFDM-based symbol over thefirst frequency sub-band of the carrier and a second OFDM-based symbolover the second frequency sub-band of the carrier, the first OFDM-basedsymbol being communicated during the same time period as the secondOFDM-based symbol.
 30. The method of claim 24, wherein the firstnumerology of the first frequency band is different than the secondnumerology of the second frequency band such that the first OFDM-basedsignal is communicated in accordance with at least one differentphysical layer parameter than the second OFDM-based signal.
 31. Themethod of claim 30, wherein the first OFDM-based signal is communicatedin accordance with a different transmission time interval (TTI) than thesecond OFDM-based signal.
 32. The method of claim 30, wherein the firstOFDM-based signal carries symbols having a different symbol durationthan symbols carried by the second OFDM-based signal.
 33. The method ofclaim 30, wherein the first OFDM-based signal carries symbols having adifferent cyclic prefix (CP) length than symbols carried by the secondOFDM-based signal.
 34. The method of claim 30, wherein the firstOFDM-based signal and the second OFDM-based signal are communicated oversub-carriers that have a different sub-carrier spacing than one another.35. The method of claim 30, wherein numerologies of the first frequencyband and the second frequency band are based on bandwidths of therespective frequency bands, the first frequency band having a differentbandwidth than the second frequency band.
 36. The method of claim 30,wherein the first frequency band and the second frequency band have thesame bandwidth.
 37. The method of claim 24, wherein the first frequencyband and the second frequency band are separated by a guard band that isless than or equal to twenty multiples of a sub-carrier spacing of oneof the first frequency band and the second frequency band.
 38. Themethod of claim 37, wherein the guard band is less than or equal to tenmultiples of the sub-carrier spacing of one of the first frequency bandand the second frequency band.
 39. The method of claim 37, wherein theguard band is less than or equal to five multiples of the sub-carrierspacing of one of the first frequency band and the second frequencyband.
 40. The method of claim 37, wherein the guard band is less than orequal to three multiples of the sub-carrier spacing of one of the firstfrequency band and the second frequency band.
 41. The method of claim37, wherein the guard band is equal to the sub-carrier spacing of one ofthe first frequency band and the second frequency band.
 42. The methodof claim 24, wherein the first frequency band and the second frequencyband are contiguous in the frequency domain such that the firstfrequency band and the second frequency band are not separated by aguard band.
 43. The method of claim 42, wherein the first frequency bandand the second frequency band have different bandwidths.
 44. The methodof claim 42, wherein a bandwidth of the frequency band is equal to orgreater than 40 megahertz (MHz).
 45. A receive point comprising: aprocessor; and a computer readable storage medium storing programmingfor execution by the processor, the programming including instructionsto: receive a first orthogonal frequency division multiplexing(OFDM)-based signal over a first frequency sub-band of a carrier and asecond OFDM-based signal over a second frequency sub-band of thecarrier, the first frequency sub-band having a first bandwidth and afirst numerology based on the first bandwidth, the second frequencysub-band having a second bandwidth and a second numerology based on thesecond bandwidth.